CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Via Matteo del Ben, 5/b, 38068, Rovereto, Italy.
Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
Eur J Appl Physiol. 2021 Jul;121(7):2061-2076. doi: 10.1007/s00421-021-04678-5. Epub 2021 Apr 3.
This study investigated the effect of performing hypoxic exercise at the same heart rate (HR) or work rate (WR) as normoxic exercise on post-exercise autonomic and cardiovascular responses.
Thirteen men performed three interval-type exercise sessions (5 × 5-min; 1-min recovery): normoxic exercise at 80% of the WR at the first ventilatory threshold (N), hypoxic exercise (FiO = 14.2%) at the same WR as N (H-WR) and hypoxic exercise at the same HR as N (H-HR). Autonomic and cardiovascular assessments were conducted before and after exercise, both at rest and during active squat-stand manoeuvres (SS).
Compared to N, H-WR elicited a higher HR response (≈ 83% vs ≈ 75%HRmax, p < 0.001) and H-HR a reduced exercise WR (- 21.1 ± 9.3%, p < 0.001). Cardiac parasympathetic indices were reduced 15 min after exercise and recovered within 60 min in N and H-HR, but not after H-WR (p < 0.05). H-WR altered cardiac baroreflex sensitivity (cBRS) both at rest and during SS (specifically in the control of blood pressure fall during standing phases) in the first 60 min after the exercise bout (p < 0.05). Post-exercise hypotension (PEH) did not occur in H-HR (p > 0.05) but lasted longer in H-WR than in N (p < 0.05).
Moderate HR-matched hypoxic exercise mimicked post-exercise autonomic responses of normoxic exercise without resulting in significant PEH. This may relate to the reduced WR and the limited associated mechanical/metabolic strain. Conversely, WR-matched hypoxic exercise impacted upon post-exercise autonomic and cardiovascular responses, delaying cardiac autonomic recovery, temporarily decreasing cBRS and evoking prolonged PEH.
本研究旨在探讨在相同心率（HR）或工作率（WR）下进行低氧运动对运动后自主神经和心血管反应的影响。
13 名男性进行了三次间隔型运动测试（5×5 分钟；1 分钟恢复期）：第一通气阈（VT1）时 80%WR 的常氧运动（N）、相同 WR 的低氧运动（FiO=14.2%）（H-WR）和相同 HR 的低氧运动（H-HR）。在运动前后，无论是在休息时还是在主动蹲起动作（SS）期间，都进行了自主神经和心血管评估。
与 N 相比，H-WR 引起更高的 HR 反应（≈83%vs ≈75%HRmax，p<0.001）和 H-HR 降低的运动 WR（-21.1±9.3%，p<0.001）。运动后 15 分钟，心脏副交感神经指数降低，N 和 H-HR 在 60 分钟内恢复，但 H-WR 后未恢复（p<0.05）。H-WR 在运动后即刻改变了心脏压力反射敏感性（cBRS），无论是在休息时还是在 SS 期间（特别是在站立期间血压下降的控制方面），在运动后 60 分钟内（p<0.05）。H-HR 没有发生运动后低血压（PEH）（p>0.05），但 H-WR 比 N 持续时间更长（p<0.05）。
适度 HR 匹配的低氧运动模拟了常氧运动的运动后自主神经反应，而不会导致明显的 PEH。这可能与降低的 WR 和相关的机械/代谢应激有关。相反，WR 匹配的低氧运动影响了运动后的自主神经和心血管反应，延迟了心脏自主神经恢复，暂时降低了 cBRS，并引发了长时间的 PEH。
